In the petroleum industry, the uses of corrosion inhibitors are meant to control corrosion of metals in a wide variety of mediums and conditions. The interaction between the active component and the metallic surface plays a determining role in its development and consequently in the corrosion control. The aforesaid interaction depends mainly on the chemical properties of the active compound thereby depending on its molecular structure, on physical and chemical properties of the metal and its interaction with the surrounding medium.
In the particular case of transportation of petroleum products through pipelines or other means such as tankers, the corrosion occurs due to the presence of water and dissolved gases in the products. The use of inhibitors such as nitrogenous compounds i.e., ammonium quaternary salts, amines, amides and including amino acids, organic polycarboxylic acids particularly the use of fat imidazolines and fat amines as corrosion inhibitors in the petroleum industry is well known.
U.S. Pat. No. 2,668,100 discloses that certain carbocyclic monocarboxy acid salts of glyoxalidines are effective corrosion inhibitor for hydrocarbon liquids. The corrosion inhibitor is applied in higher concentration of 25-50 ppm to get better corrosion inhibition.
U.S. Pat. No. 2,944,968 discloses the use of diamides as ferrous metal corrosion inhibitor for hydrocarbon fluids. These diamides were synthesized from polyalkyleneamines and monocarboxy acid. The alkylene part of the polyalkyleneamines may contain as many as six carbon atoms.
U.S. Pat. No. 2,736,658 describes the invention of a class of organic compound to protect ferrous metal surfaces from corrosion. They have designed a class of organic amine and acid salt prepared from N-aliphatic or alicyclic substituted polymethylene diamines those contains aliphatic or alicyclic carbon chain of 8 to 22 and from 2 to 10 number of methylene groups with a resin acid or fatty acid.
U.S. Pat. No. 4,148,605 discloses a dicarboxylic ester-acid obtained from the condensation of an alkenylsuccinic anhydride with an aliphatic hydroxy acid having from 2 to about 18 carbon atoms and amine salts of said ester-acid are useful as rust or corrosion inhibitors for metal surfaces which is in contact with organic media such petroleum distillate hydrocarbon fuels.
U.S. Pat. No. 4,214,876 discloses an improved corrosion inhibitor composition for hydrocarbon fuels. This corrosion inhibitor consisting of mixtures of (a) about 75 to 95 weight percent of a polymerized unsaturated aliphatic monocarboxylic acid having about 16 to 18 carbons, and (b) about 5 to 25 weight percent of a monoalkenylsuccinic acid wherein the alkenyl group has 8 to 18 numbers of carbon atom.
U.S. Pat. No. 5,853,619 discloses the use of corrosion inhibitor for ferrous metal in oil and gas-field application. The corrosion inhibitor comprises of (A) mercaptocarboxylic acid having 2 to 6 carbon atoms, and (B) a polyamine/fatty acid/carboxylic acid adduct. Their preferred combination of (A) and (B) includes mercaptoacetic acid and ethylenetetramine/tall oil acid/acrylic acid adduct. A number of additives have already been reported as corrosion inhibitor for pipelines.
U.S. Pat. No. 4,028,117 discloses development of an improved corrosion inhibitor for pipelines used in transportation of hydrocarbon liquids such as crude petroleum or refined petroleum fractions. The developed corrosion inhibitor comprises of a mixture of (a) 1.8 to 25 parts by weight of dimerized unsaturated fatty acid, and (b) 1 part by weight of an alkoxylated alkyl phenol.
From the above prior arts, it is evident that researchers have in the past developed several products based on polycarboxylic acids, amide or mixture of amine salt of dimer fatty acid. Most of those commercial corrosion inhibitors are not effective at dosage rate in the range of 6 to 23 ppm. Therefore, finding a high performing cost effective product for application as corrosion inhibitor is well desired.